Telephone-exchange system.



No. 68I,724. Patented Sept. 3, I90I. J. L. MOUUARRIE.

TELEPHONE EXCHANGE SYSTEM.

(Application led Nov. 10* 189B.)

(No Model.)

Baar'iZ UNiTnD STATES PATENT OFFICE.

JAMES L. MCQUARRIE, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 681,724, dated September 3, 1901.

Application led'November l0, 1898. Serial No. 696,028. (No model.)

To @ZZ whom t may concern:

Be it known that I, JAMES L. MCQUARRIE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Telephone-Exchange Systems, (Case No. 5,) of which the followingis a full, clear, concise, and exact description. My invention relates to telephone-exchange 1o systems wherein a number of operators l0- cated at different switchboards of the system are employed in supervising each connection between subscribers, and has for its object the provision of improved means for automatically conveying intelligence between the operators as to the condition of use of the Various instrumentalities employed in establishing and severing connections.

One feature of my invention is of particu- 2o lar utility in connection with systems employing a multiple switchboard for one group of telephone-lines and another switchboard of any type separated from the multiple switchboard for another group of telephone-lines, between which boards apparatus is disposed for connecting subscribers upon one board with subscribers upon the other board. In systems of this character I propose to assign an operator one section of the multiple board, 3o whose sole duty it is to connect or disconnect at her section trunk-lines extending between the boards with or from calling or called lines. This operator preferably is not informed whether the line with which she is to establish connection is a calling or a called line, but is merely informed of the number of the line-jack into which she is to insert a trunk-line plug, it being the du ty of other 0perators in the system to perform the remain- 4o ing acts in establishing a connection. Ihave provided an improved testing system whereby the trunk-line operator may absolutely determine the condition of use of the selected line, thus obviating a false test when the trunk-line operator is instructed to make connection with a calling-subscribers line at her section. If a subscriber of the multiple switchboard should desire a connection with a subscriber at the other board, the operator 5o at the section containing the calling-subscribers line-annunciator by inserting an answering-plug would establish a condition for erroneously indicating to the trunk-line operator when she tests that theline is busy if it were not for my improved test system. This feature of my invention in its preferred embodiment consists in establishing through the agency of apparatus associated with the switching appliances a test which is distinctive from the test regarded bythe operators 6o in establishing connections between subscribers of the same multiple switchboard, this special test being preferably established in part through the agency of the connecting apparatus employed in answering a call reoeived at any of the sections of the multiple switchboard, so that the trunk-line operator upon noting this special test or upon noting that the line is not in use will finish the connection. If she should note the ordinary 7o test, unaccompanied by the special test, she would inform the calling subscriber that the line was busy.

A second feature of my invention consists in apparatus located at the diferent operators boards for automatically eifecting the operation of signal appliances which will indicate to the operators the acts they are to perform in manipulating the switching apparatus. This feature of my invention in one 8o of its aspects may generally be described as consisting in an operators indicator at one board or section, a source of current for operating the operators indicator or signal, and means controlled by another operator for governing the operative eect of the current as it iiows through the signal. I mayprovide a plurality of paths for the current from said source, more or less of which are closed in effecting the operation of the signal. In an- 9o other embodiment of the invention I have employed two sources of current in combination with apparatus which would serve to cause the current from the two sources to flow in opposite directions through a signal, so that the electromotive forces would oppose each other to maintain the signal in one condition of use, the switching apparatus being adapted to rearrange the sources of electricity to increase the effective current iiowing loo I will eXplain my invention more particularly by reference to the accompanying drawing, which illustrates the preferred embodiment thereof. This drawing is a diagram of the circuits of a subscribers line and a tollline entering different switchboards, with the usual operators apparatus for uniting the lines in the subscribers switchboard and trunk-lines for uniting the two lilies thus entering the switchboard.

The apparatus at the subscribers station comprises a call-bell, a transmitting and a receiving telephone, an induction-coil, a telephone-switch, and condenser. The circuit is normally completed through the bell and condenser; but when the telephone is taken for use the telephone-switch closes the bridge of the line through the transmitter and aV winding of the induction-coil and also completes a local circuit olf the transmitting-telephone containing the condenser and the other winding of the .induction-coil.

In the drawing I have illustrated a subscribers station 401 connected with the sections of a multiple switchboard D, the line being associated with a familiar relay apparatus a, for controllingr the line-indicator ct. The test-rings of the spring-jacks are grounded through a coil of one of the relays, as shown. The sections l, 2, 3, and 4 are ordinary sections of multiple switchboard at which calls may be initiated. Section 5 preferably has no line-annunciators and is attend-ed by a trunk-line operator for establishing connection between subscribers of the multiple board and the subscribers at any other board than boa-rd D. The operator at section 4, whom I term the A operator, is provided with several pairs of cords and plugs. Associated with the tip and sleevestrand of each cord-circuit or line-connecting apparatus is the apparatus illustrated, which is now commonly employed in telephony. Between the third or test thimble contacts of the plugs is included a conductor containing clearing-out signals b b', about which shunts are established when the armatures of the relays included in the sleeve-strand of the cordcircuit are attracted, as is well understood. In each shunt-circuit a helix b2 of an induction-coil is included, a grounded conductor including a battery b3 being connected between the helices of the induction-coil. The coils b2 b2 of the induction-coil are thus each included in a local circuit, current beinginduced in one local circuit from the other local circuit for the purpose of testing, as hereinafter specified. The answering-plug is inserted within a line-jack of a calling subscriber 401. The connecting-plug is inserted within the spring-jack b4 of a trunk-line eX- tendng between the A operator and the B operator located at a switchboard E. The cordconnecting apparatus is connected, as shown, when a subscriber of the multiple switchboard desires connection with a subscriber of the other board. Upon the insertion of the t tation.

connecting-plug in the jack b4 suliicient current is directed from the battery b3 through the lamp c to cause the same to glow. The B operator thereupon momentarily places the plug d within the trunk-line jack CZ', whereby the three springs of the jack are removed from their normal contacts, the spring d2 being brought into engagement with its alternate contact to establish a path of lower resistance for the current from battery b3 through the relay e than the branch includ-- ing the lamp c affords, the said relay being thereupon energized to attract its armature, which serves to close another path of low resistance through the relay, whereby upon the withdrawal of the plug d the armature of the relay remains attracted. The circuit from the battery b3, including the said relay, affords a path of lower resistance than the circuit including the lamp c, the said lamp thereupon being extinguished. The current through the indicator h is by the same means increased sufficiently to cause the said lamp to glow. The parts at the jack d are indicated in the position they occupy when the plug d has been withdrawn.

I have shown means for producing a vibrating current f in a local circuit to produce a current capable of creating a distinctive tone when included in circuit with an operators telephone, the induction-coils f and b2 being provided for propagating this current to the test-thimbles of the various spring-jacks connected with the third cont-acts ot the A oper-l ators plugs, including the test-thimble at the C operators section of the multiple board. Thus the A operator by means of her answering-plug establishes one lform of test-circuit adapted to produce one test manifestation,- while by her connecting-plug she is able to apply a different testing-cu rren t,-which serves to, produce a second and distinctive manifes- This current is not of a character suited to the effective energization of the relay e. The calling subscriber 401 desiring connection with a subscriber of a toll-line board, for example, announces to the A operator toll-line.7 The A operator connects the calling subscriber with the B operator by inserting the connecting-plug into the jack b4, as hereinbefore described. The operator B inserts plug d and ascertains from the calling subscriber the particular toll-line with which connection is desired. The B operator thereupon proceeds to insert the connectingplug g within thejack of the toll-line subscriber and notities hiin by operating the ringing-key g. She also operates the listening-key h to ascertain from the O operator the particular trunk-line between her board and the board of operator C that she may employ, at the same time notifying operator C to make connection with line 401. The B operator then inserts the plugz' within the jack of the selected trunk-line. The operator C,

not knowing whether the line 401 is a calling or called line, tests, Vibrating current from IOO the device f creating a peculiar tone in her 'telephone in addition to the ordinary test manifestation. This tone indicates to this operator that subscriber 401 is the calling subscriber, and she thereupon inserts the plug 7c of the selected trunk-line within the jack 401. Upon the insertion of plug 7c an additional path is afforded for the current from battery b3 through the lamp h, which may be traced from the contact -thimbles of the multiple switchboard through the engaging contact of' plug k, plug-seat switch-contact lo', to ground k2. This path being of lower resist-ance than the path including the grounded-line relaymagnet serves to increase the current through lamp h, which thereupon glows. The A operator upon noticing the signal given by lamp b removes the plugs from their engaging jacks, the connection between the subscribers being maintained by the apparatus in charge of operators B and C. The lamps and m are the clearing-outindicators. When the subscribers are through with their conversation,they restore their telephonesto their switch-hooks, the switch at station 401 serving to open the circuit including the relay governing the indicator or lamp Z, the shunt established about said indicator during the established telephonie connection between the subscribers being broken, whereupon the lamp glows. In response to the signal the B operator withdraws plug t from the trunkline jack, whereupon the battery l', which was opposed to battery m' during the established connection, is removed, the battery m then causing the lamp m to glow, the circuit being traced from ground m2 through the plug-seat switch-contacts 71:3, lampm, and battery m' to ground k2. In response to this signal operator C withdraws the plug 7s. If a toll-line subscriber calls for a multiple-switchboard subscriber,the A operator takes no part in establishing the connection. The B operator, who receives this call, notifies the operator C, as before, who tests to find whether the multiple-switchboard subscriber is busy, as heretofore, the tone test never being manifested when the toll-line subscriber is the calling subscriber. v

I have not seen t particularly to describe all of the instruinentalities entering into the illustrated embodiment of my invention, as they are all clearly shown diagrainmatically. It is obvious that there are certain features of my invention which are adapted for use in connection with other telephone-exchange systems than the system shown, and I do not therefore desire to be limited to the precise apparatus and system shown; but,

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a telephone-exchange system, the combination with a telephone-line terminating in line-switches at sections ofa multiple switchboard, of a second telephone-line terminating at a second switchboard, a pair of connecting-plugs at one section of the multiple switchboard, a trunk-line extending between' the latter section of the multiple switchboard and the second board adapted to be united with the first telephone-line by the connecting-plugs, a second trunk-line between said boards and extending to a second section of the multiple switchboard, switching apparatus at the second board for connecting the operators telephone thereat with conductors extending to both sections of the multiple switchboard and for connecting the second trunk-line with the telephone-line extending to the second board, switching apparatus at the second section of the multiple switchboard for uniting the second trunk-line with the first aforesaid telephone-line, one testcircuit at the multiple switchboard controlled by one of the aforesaid plugs, a second testcircuit at the multiple switchboard controlled by said connecting-plugs and apparatus associated with the first-aforesaid trunk-line, test-contacts associated with theline-switches at the sections of the multiple switchboard and with said test-circuits, and a testing appliance at the second section of the multiple switchboard, the test-circuits serving to produce test manifestations differing from each other, substantially as described.

2. In atelephone-exchange system,the combination with a telephone-line terminating in line-switches at sections of a multiple switchboard, ofa second telephone-line terminating at a second board, a trunk-line extending between the second board and a section of the multiple switchboard, a second trunk-line extending between the-second board and another section of the multiple switchboard, switching apparatus at the second board for connecting the operators telephone in circuit with conductors extending to the said sections of the multiple switchboard and for uniting the second telephone-line with the second trunk line, switching apparatus at the second section of the multiple switchboard for connecting the second trunk-line with a switch of the first-aforesaid telephoneline, a switch for the first trunk-line, a cordcircuit at the first section of the multiple switchboard for forming a continuation of the first-aforesaid telephone-line, a connecting-plug forconnecting the cord-circuit with the first trunk-line, thimbles or terminals associated with the switches of the first telephone-line and the latter trunk-line, a source of current connected or adapted to be connected with the thimble associated with the switch of the rst trunk-line, a contact portion carried by the connecting-plug adapted to engage the latter contact-thimble, means for charging the test-thimbles associated with the switches of the first-aforesaid telephoneline with current from the said source thus connected with the said contact portion of the connecting-plug, and a testing appliance at the second section of the switchboard, substantially as described.

IOO

IIO

3.V In a telephone-exchange system,the combination with a telephone-line terminating in switch for the latter line; a cord-circuit for` forming a continuation of the first-aforesaid telephone-line; a connecting-plug for connecting the cord-circuitwiththe second line thimbles or terminals associated with the switches of 'each of the said li-nes; a source of current connected with or adapted to be connected with the thimble associated with the switch of the second line; a local circuit including said source of current, the contact portion of the connecting-plug and the thimble engaging said contact portion; a coil of an induction-coil included in said local circuit, and a test-circuit connecting the second coil of said induction-coil with the thimbles associated with the line-switches of the first-aforesaid telephone-line, substantially as described.

f4. In a telephone-exchange system,the com` bination with a telephone-line terminating in line-switches at sections of a multiple switchboard, of a second line, as a trunk-line, a switch for the latter line, a cord-circuit for forming a continuation of the first-aforesaid telephone-line, a connecting-plug for connecting the cord-circuit with the second line, thimbles or terminals associated with the switches of each of the aforesaid lines, a source of current connected or adapted to he connected with the thimble associated with the switch of the second line, a contact portion carried by the connecting-plug, and means for charging the test thimbles associated with the switches of the first-aforesaid telephone-line with current from the said source of electricity thus connected with the said contact portion of the connecting-plug, substantially as described.

5. Inatelephone-exchangesystem,thecombination with a telephone-line terminating in line-switches at sections of a multiple switchboard, of a second line, as a trunk-line, a switch for the latter line, a cord-circuit for forming a continuation of the first-aforesaid telephone-line, a connecting plug or part for engaging the latter switch adapted to connect the cord-circuit with the second line, a testcircuit governed by said connecting-plug and apparatus associated with the second line, and test-contacts at the different sections of the switchboard associated with said test-circuit and the line-switches of the rst telephoneline, substantially as described.

6. Inatelephone-exchange system,the combination with two switchboards; of a trunkline between said boards; switching apparatus at one of said boards for connecting a telephone-line with said trunk-line; a clearingout indicator for the said telephone-line; a second clearing-out indicator at the remaining board; a closed circuit including the second clearing-out indicator and a source of current; and a second source of current included by the switching apparatus at the first board (upon connecting the telephone-line with the trunk-line) in circuit with the lirst-aforesaid clearing-out indicator and with a conductor included in the circuit of the second clearingout indicator, the current from the sources of electricity being opposed, substantially as described.

7. In a telephone-exchange system,the combination with two switchboards, of a trunkline signaling-circuit extending between the boards, a source of current and a signal included in the circuit at each board, said sources of current being opposed to one another, a connection rm2 from the circuit between the two signals to a return-circuit with which the two sources of current are connected, and a switch at one of the boards adapted to open the circuit between the signal at that board and the connection m2, substantially as Set forth.

8. In a teleph one-exchan ge systen1,the combination with two switchboards; of a circuit between the same including a signal at each of said boards, switching apparatus at one of said boards for opening and closing said signal-circuit, said circuit including a source of current and a resistance; a path of low resistance; and means for closing the same about said resistance and one of said signals, substantially as described.

9. The combination with two switchboards of a circuit between the same including a signal at each of said boards; switching apparatus at one of said boards for opening and closing said signal-circuit; a source of current and a resistance in said circuit; a relay; a spring-jack; and a plug for insertion within the spring jack, said spring -jack serving upon the insertion of the plug to close circuit through the relay, the armature of the relay serving also when attracted to close circuit through the relay, the relay-circuit forming a path of low resistance about said resistance and one of said signals, the aforesaid switch- IOO IIO

1l. In a telephone-exchange system, the

rst board for associating said test-circuit with the said test-contacts, substantially as described.

12. In a telephone-exchange system, the combination with a telephone-line extending to a switchboard, of a second telephone-line having terminals upon sections of a multiple switchboard and extending to the first-aforesaid board by means of suitable connecting apparatus, test-contacts for the second telephone-line, two test-circuits each capable of producing a test manifestation differing from that produced by the other, means at the multiple switchboard for associating one of said test-circuits With said test-con tacts, and means at the remaining switchboard for associating the other test-circuit with said testcontacts, substantially as described.

13. In a telephone-exchange system, the combination with a telephone-line with terminals thereof on several sections of a multiple switchboard and test-contacts for the line,

' of a source of characteristic testing-current and a signal at one of the boards and means for connecting them With the telephone-line at the said board, means for testing the line at each of tho other boards, and circuit connections at one of said boards closed in making connection with the line adapted to display the signal at said first-mentioned board; whereby a characteristic test-current is ap plied to the linc in making connection at one ofthe boards, and the establishment of connection with the line at another board signals for the disconnection of said characteristic testing-current, as described.

14. In a telephone-exchange system, in combination, two telephone-circuits, one of said circuits being connected with terminals in different sections of a multiple switchboard, link conductors uniting the circuits, a source of characteristic testing-current connected with the other circuit, said characteristic testing-current being impressed on the test-contacts of the multipled circuit through the agency of said link conductors, as described.

In witness whereof I hereunto subscribe my name this th day of July, A. D. 1898i JAMES L. MCQUARRIE.

Witnesses:

GEORGE L. CnAcc, WINFIELD W. W. LEAcI-r. 

